1. Field
The subject invention is in the field of suspension systems for vehicles, i.e. the springs, shock absorbers and mechanism interconnecting the wheels of the vehicle with the primary vehicle structure and mass. In particular it is in the field of suspension systems for the front wheel of a motorcycle.
2. Prior Art
There are two popular types of conventional suspension systems for the front wheel of motorcycles. One type comprises two telescopic struts, one on each side of the wheel. The wheel axle is attached at the lower end of the lower element of each strut. Springs are housed in the struts and they may incorporate shock absorbing features also. A second type comprises struts, levers, links and springs. The wheel axle is carried at one end of each of two short levers. The other ends of these levers are attached to the lower ends of struts extending from the steering pivot. Links are pivotally attached to the levers at points between their ends and these links extend generally upward to be engaged by springs.
These prior art suspensions tend to be relatively expensive, cluttered in appearance and do not have adjustable spring rates to adjust the ride to suit the driver. Also, they are considered marginally stiff in torsion between the wheel and the head end attached to the motorcycle frame. Accordingly, the objective of the subject invention is to provide a motorcycle front wheel suspension which is relatively torsionally stiff, compact, uncluttered in appearance, and has an adjustable spring rate and a dedicated air source.
The subject invention is a suspension system for the front wheel of a motorcycle. The system mounts on a shaft carried on roller bearings in the neck of the motorcycle frame. The shaft extends above and below the neck. Two crossbeams are attached to the shaft, one to the portion above the neck, the other to the portion below. Two struts are attached to the ends of the crossbeams and extend downward to form the fork assembly to which the wheel is attached. Two links are pivotally attached at one of their ends to the lower ends of the fork struts. The front wheel axle is attached to their other ends. A suspension strut is also attached to each of these ends and the axle. The suspension struts are parallel to the fork struts and their upper ends are attached to a crosshead, the crosshead being guided in slots in the fork struts. Two pneumatic springs are installed between the crosshead and the underside of the upper crossbeam. The axle moves essentially parallel to the plane of the fork struts against the forces applied by the springs. The spring rate is adjusted by adjusting the pressure in the pneumatic springs.
The invention also includes a pressure air source installed on the motorcycle to provide pressure air to the springs.
The invention is described in more detail below with reference to the attached drawings.